It is impossible to answer a simple yes or no to this question.
You see it somewhat correctly, many altcoins are more risky, offering higher chances of growth but higher chances of failure, too. However, making the right decision takes a more nuanced approach.
First of all, there is bitcoin and bigger, older altcoins such as ethereum, which can be considered safer options, and there are smaller, younger altcoins that are more of a gamble. For this reason, diversification is important - you can mitigate your overall risks if you invest a part of your money in safer coins while experimenting with the more volatile ones.
Secondly, not all altcoins are made the same. You should always do ample research before choosing a riskier coin so you can decide for your own whether it is worth taking the risk.